In the design of internal combustion engines it has long been recognized that achievement of optimum fuel/air mixtures is a principal factor in improving efficiency. The fuel will then be burned as completely as possible. Completely burning the fuel obviously results in extracting the maximum amounts of energy from each gram of fuel and eliminates unburned or partially burned fuel in the engine exhaust which is the source of most undesirable emission products.
In the past, carburetors and fuel injectors generally have provided a fuel/air mixture in atomized or vaporized form. These mixtures tend to consist of finely divided droplets of fuel suspended in air as a vapor. Very little, if any, pure gaseous fuel is produced in the typical prior art carburetor or fuel injector. Generally, designers of carburetors and fuel injectors have attempted to get a finer and more uniform distribution of fuel droplets within the fuel/air mixture. However, as the droplets become finer or smaller in diameter, the droplet surface tension becomes greater and further reduction to a true gaseous state comprising fuel molecules mixed with air molecules becomes difficult to achieve.
The desirability of providing fuel for an internal combustion engine in a pure gaseous or super heated form has been recognized in the prior art. For example, in U.S. Pat. No. 4,083,340 which issued on Apr. 11, 1978 to Clen Furr et al a method of superheating gasoline is described. In the Furr et al method, the heat from the cooling system of an internal combustion engine is used to heat gasoline under pressure in a chamber above the normal boiling point of gasoline. When pressure is reduced, the gasoline is converted to a gas and liquid fuel. The gaseous fuel is fed to the intake of an internal combustion engine and the liquid fuel is recycled back to the fuel pressure chamber. However, this method requires the heating of a highly flammable fuel under pressure with the obvious risk such heating involves. Accordingly, it is one object of the present invention to provide a method and apparatus for producing fuel for an internal combustible engine in a purely gaseous state or a mixture of gas and very fine, invisible droplets without the necessity of heating the fuel.
It is known in the prior art to heat the intake manifolds of an internal combustion engine so that the atomized fuel mixture will be expanded and be more like a true gas as it enters the combustion chamber of the engine. However, heat must be added to the manifold. Accordingly it is another object of the present invention to provide a method and apparatus for converting an atomized fuel into a gaseous state without the addition of heat energy, that is, fuel in a gaseous state or is near that of super heated fuel is provided immediately at the start of engine, with no superheated fuel reservoir required. The gasification units of my invention are at optimum speeds immediately prior to engine ignition because the engine start-up and gasification units can start-up simultaneously.
In another prior art device disclosed in U.S. Pat. No. 4,515,134 to Conrad K. Warren which issued May 7, 1985, a "Molecular Diffuser Assembly" is described in which a thermistor-type heater/evaporator is used to vaporize the volatile constituents of a fuel. When substantially vaporized, the fuel is introduced into a venturi for diffusion into an air stream passing therethrough. The air stream is delivered into the combustion chamber of an internal combustion engine. Again, it is an object of the present invention to avoid the necessity of heating fuel or atomized fuel before delivering it to the combustion chamber of an internal combustion engine.
In the prior art, significant effort has been devoted to reducing the emission products from an internal combustion engine and among these undesirable products are the unburned hydrocarbons and the oxides of nitrogen. In addition to catalytic converters, as one means to reduce these emissions and suppress premature ignition, it is common design practice to equip an engine with an exhaust gas re-circulation valve (EGR.) Another method is to inject water into the atomized fuel/air mixture. These prior art methods and devices require complicated valving and the supply and delivery of another material, namely, water or exhaust gases. Accordingly, it is still a further object of the invention to provide an apparatus and method to reduce the emission of undesirable combustion products without the necessity for water injection and to minimize the need for re-circulation of exhaust gases.
While there have been many other prior art attempts to successfully superheat or gasify fuel in order to provide a more efficient internal combustion engine with reduced exhaust contaminants my invention as described below generally achieves all these objects with a novel method and apparatus.